We propose the development of a low cost instrument capable of recording the fetal magnetocardiogram (fetal-MCG). This totally non-invasive instrument is intended to contribute to the assessment of fetal stress and the diagnosis of fetal cardiac arrhythmias. The fetal-MCG system provides unique information that is difficult or impossible to obtain with any other instrument. HYPRES, Inc., a world leader in superconducting electronics, is teaming for this project with Biomagnetic Technologies, Inc., the pioneer and leading supplier of biomagnetometer systems. Professor John Wikswo of Vanderbilt University, a leading researcher in biomagnetism will be a consultant. The program will also benefit from collaborative research with Norman H. Silverman, M.D., D.Sc. (Med), Professor of Pediatrics and Radiology (Cardiology) at the University of California, San Francisco. Dr. Silverman is well-known for his work in fetal echocardiography. The proposed instrument will utilize, for the first time, digital SQUIDs for the critical sensor component of the system. The use of this new digital SQUID technology will dramatically reduce the cost of the system by eliminating the need for a very expensive shielded room and by simplifying the electronics. In Phase I we will develop the digital SQUID circuit, design the complete system, and calculate the expected system performance characteristics. In Phase Il we will produce and demonstrate at least one complete prototype suitable to initiate detailed clinical studies. PROPOSED COMMERCIAL APPLICATION: The instrument developed has the potential of becoming an essential tool for diagnosing fetal stress. Such a low cost system could find widespread use in all secondary care and many primary care obstetric practices. The ability of the system to diagnose fetal cardiac arrhythmias would find use in tertiary care settings. The use of digital SQUIDs in this instrument will lead to significant savings in the fetal-MCG system cost due to the elimination of the need for a shielded room and the simplification of the electronics. The successful demonstration of the digital SQUID technology here would also open the door for commercialization into other biomagnetometer applications including Magnetic Source Imaging to localize brain function for surgery or epilepsy treatment, and to localize cardiac arrhythmogenic tissue or to determine patients at risk for sudden cardiac death.